01 Snippet

# Source URL: https://dev.epicgames.com/community/snippets/oYRX/fortnite-generic-sync-and-race-across-elements-in-an-array
# Local doc:  epic-docs/community/snippets/oYRX/fortnite-generic-sync-and-race-across-elements-in-an-array.md
  using { /Verse.org/Simulation }
  # ArrayRace will call the Function argument for each element in the Array and wait for only one of the async functions to complete, canceling all the rest.
  # A divide-and-conquer concurrency algorithm that divides an array into two and races between the two subarrays.
  # This is a recursive implementation, where the function calls itself to race between the divided arrays.
  # The base case (the condition to stop the recursion) is the array has only one element.
  # This is a generic implementation using parametric types, so you can provide your own type and your own async function as arguments.
  ArrayRace(Array:[]t, Function(Element:t)<suspends>:u where t:type, u:type)<suspends>:u=
  # If more than two elements in the array, then split the array in half,
  # and race between the subarrays recursively.
  if:
  Array.Length > 1
  Mid := Floor(Array.Length / 2)
  LeftArray := Array.Slice[0, Mid]
  RightArray := Array.Slice[Mid]
  then:
  race:
  ArrayRace(LeftArray, Function)
  ArrayRace(RightArray, Function)
  else if:
  First := Array[0]
  then:
  # Grab the only element in the array and call the async function with it as the argument.
  Function(First)
  else:
  # A race with no subtasks never completes, so sleep infinitely and call Err() because we shouldn't return a value here.
  Sleep(Inf)
  Err()
  # ArraySync will call the Function argument for each element in the Array and wait for all the async functions to complete.